Electronic timepiece



Dec. 2, 1969 M. HETZEL ETAL ELECTRONIC TIMEPIEGE 5 Sheets-Sheet 1 FiledSept. 12, 1966 Dec. 2, 1969 M. HETZEL ETAL 3,481,137

' ELECTRONIC TIMEPIECE Filed Sept. 12, 1966 5 Sheets-Sheet 2 De 1969 M.HETZEL ETAL ELECTRONIC TIMEPIECE 5 Sheets-Sheet 3 Filed Sept. 12, 1966Dec. 2, 1969 M. HETZEL. ETAL ELECTRONIC TIMEPIECE 5 Sheets-Sheet 4 FiledSept. 12, 1966 mm mm mm 2 whim D 1969 M. HETZEL ETAL 3,

ELECTRONIC TIMEPIECE Filed Sept. 12, 1966 5 Sheets-Sheet 5 3,481,137ELECTRONIC TIMEPIECE Max Hetzel, Bienne, Henri Haring, Tavannes, andHenri Robert, Chaux-de-Fonds, Switzerland, assignors to CentreElectronique Horloger S.A., Neuchatel, Switzerland Filed Sept. 12, 1966,Ser. No. 578,535 Claims priority, application Switzerland, Sept. 13,1965, 12,678/ 65 Int. Cl. G04c 3/00 US. Cl. 5823 7 Claims ABSTRACT OFTHE DISCLOSURE In an electronic timepiece including a base plateindependently carrying both a movement cage and the foot of a resonatorwhich is electrically maintained, wherein the resonator constitutes thetime base and the driving member for the movement, there is provided abearing cage independent from the movement cage and connected rigidly tothe foot and including a ratched wheel; and a pawl for transmittingmotions of the resonator to the ratchet wheel, whereby the bearing cage,the movement cage and the resonator can be independently and separatelyassembled and disassembled.

In electronic timepieces employing an electro-mechanical oscillator as atime base and driving member, the transformation of the oscillatingmovement into a rotating movement for driving the clockwork is etfectedgenerally by means of a ratchet device comprising a driving pawl rigidwith the resonator, acting on a first ratchet wheel, and a stop pawl,secured on the plate of the move ment, immobilizing the ratchet wheelwhen the same is not driven by the reasonator.

The ratchet wheel is pivoted in the plate as are the other mobiles ofthe movement. The resonator, the pawls and the ratchet wheel constitutea driving assembly the members of which must be adjusted one to theother in a very precise manner. However, such an adjustment is verydiflicult under practical conditions when the resonator is madeseparately with its driving pawl, then mounted on the plate bearing theratchet wheel and the stop pawl. It has been noted furthermore that theplate often has a certain flexibility so that the stop pawl can moresufiiciently with respect to the driving pawl so as no longer becorrectly in phase with the driving pawl.

The present invention has for object an electronic timepiece the timebase of which and the driving member of which consist of a reasonatorelectrically upkept and driving the movement by means of a pawl drivinga ratchet wheel, which timepiece does not have the drawbacksabove-mentioned. It is characterised mainly by the fact that the ratchetwheel is mounted in a bearing cage which is independent of the movementcage which is secured on the resonator itself.

The bearing cage can be secured by its upper bridge on the foot of theresonator. The cage can be made independently of the resonator, howeverbecause of its cantilever position on the resonator, there is the dangerof having the upper bridge bend and with it the cage would movevertically.

This can be avoided by suitable assembly.

According to another characteristic of the invention, the independentcage has two bridges secured respectively on the upper and lower facesof the foot of the resonator securing the resonator to the plate.

This arrangement is made practically possible thanks to the greatprecision which can be obtained by the current milling processes forshaping the thickness of the resonator.

United States Patent The annexed drawing represents by way of exampletwo embodiments of the object of the invention as well as modifications.

FIGURE 1 shows a partial view of an electronic watch provided with adouble mechanical pawl arrangement.

FIGURE 2 shows a partial vertical cross-section taken along the line I-Iof the watch of FIGURE 1.

FIGURES 2A and 2B are cross-sectional views taken along lines 2A2A and2B2B, respectively.

FIGURE 3 shows a similiar assembly but provided with a clique combinedwith a magnetic gear.

FIGURE 4 shows a partial vertical cross-section of the age and of thefoot of the resonator.

FIGURES 5 and 6 show a cross-section and a plan view of a modified formof a magnetic gear. I

FIGURE 7 shows cross-sectionally a second modification of the pivotingof the magnetic gear.

The electronic watch shown on FIGURES 1 and 2, and 2A and 2B comprisesessentially a resonator 1 having two bent branches maintainedelectromagnetically. This resonator is secured by its V-shaped foot 1aby means of three screws 2, 3 and 4 on the plate 5 of the movement. Onone of the branches of the resonator is secured a driving pawl 6. Afirst ratchet wheel 18 is mounted in a cage independent of the movementcage and formed by the upper and lower bridges 7 and 8 respectively,linked therebetween by a screw 9 and two positioning pins 10 and 11. Thebearing cage is secured to the resonators foot 1a by its upper bridge 7by means of two screws 13 and 14. The reasonator and the cage thus forma unit which can be made independently of the rest of the watch. In thecage is mounted additionally a lever 15 pivoted in this cage at 16 andbearing at is extremity 15a the stop pawl 17. This lever permits toadjust the phase of the stop pawl with respect to that of the drivingpawl 6. The mobiles are formed in the order given by a first ratchetwheel 18 mounted on a shaft of a five toothed cam 19 periodicallydriving the arm 20 of a lozange shaped lever 21 at the extremity 21a ofwhich is encased a pawl 22 driving a second ratchet wheel 23 the coaxialpinion 24 of which drives the second wheel 25, the first mobile of thegear train which is pivoted on the plate of the movement. This doublepawl acts as a mechanical frequency filter between the resonator and themovement. The fact that the point of attack pawl 22 on the ratchet wheel23 is located on the other side of the perpendicular joining the shaftof the lever 21 to that of ratchet wheel 23 by the point where it isencased in lever 21 permits to obtain a simple construction which doesnot require an auxiliary return spring for lever 21.

In a preferred embodiment, the oscillating resonator has a frequency of480 cycles per second. By giving wheel 18, 240 teeth and cam 19 fiveteeth, it is seen that wheel 18 will make 2 turns per second and thateach tenth of a second, lever 20 will make one oscillation. The secondratchet wheel 23 has teeth.

In the second embodiment shown on FIGURE 3, the cage of the deviceconsists also of bridges 7 and 8 mutually connected by screw 9 and thetwo positioning pins 10 and 11, the cage being secured by its upperbridge 7 to the foot 1a of the resonator by two screws 13 and 14. Thiscage is smaller than the previous one owing to the Jse of a simplerdevice. In this device, there is again the first ratchet wheel 18 drivenby pawl 6 and held back by stop pawl 17, but rigid this time with amagnetised polar wheel 26 driving magnetically a second polar wheel 27of greater diameter and the coaxial pinion of which 28 drives anintermediate Wheel 29 the pinion of which 30 meshes with the secondwheel 25. The advantage of the magnetic gear in this particular caseconsists essentially in that the space separating the poles of wheels 26and 27 can vary by several hundredths of a millimeter without 3affecting the proper functioning of the watch, which permits to mountwheel 27 on the plate of the movement while the polar wheel 26 ismounted in the cage. The use of an independent cage for the ratchet andpawl device rigid with the resonator has in this embodiment certainevident advantages, the link between the two units formed on the onehand by the resonator and by its ratchet and pawl device and on theother hand by the movement, have a flexibility which is not present inthe first embodiment and which permits a rapid and easy assembly ofthese two units.

In the embodiment shown in FIGURE 4, the cage is no longer cantilever onthe resonator but is integral with the foot of the resonator.

In FIGURE 4 there is shown by 31a the securing foot of the resonator onplate 32 of the watch as shown .on FIGURE 1. The foot of the resonatorsecured to plate 32 of the movement by three triangularly disposedscrews two of which 33 and 34 can be seen in the drawing. The cage iscomposed of an upper bridge 35 and of a lower bridge 36 linked togetherby a screw 37 freely passing through the foot of resonator 31a andpositioned by pins 38 and 39. This arrangement not only simplifies theassembly, the number of screws and the assembling elements being reducedto a minimum, but increases the precision of positioning of the mobileswith respect to the bridge. Furthermore, the fact of placing the head ofscrew 37 on the side of the lower bridge makes it impossible to take thecage apart without previously removing the assembly of the resonator andcage from the plate.

The ratchet wheel 40 driven by the resonator pawl is riveted between theupper bridge and the lower bridge of the cage and there instead of apinion a polar magnetised wheel 41 of small diameter magnetically drivesmagnetic wheel 42 the pinion of which 43 meshes with an intermediatewheel 44 driving in its turn the dial train not shown. For reasons ofassembly, in particular for cleanliness and handling, it is advantageousto lodge the magnetic wheel 42 in the cage and not under the bridge ofthe gear train. The upper pivot 44' of the magnetic wheel turns in abearing of the upper bridge 35 while its lower pivot 45 turns in abearing mounted in plate 32. The lower pivoting of the magnetic wheeland of its pinion and the lower pivoting of the intermediate wheel 44are thus located in the same constructional element 32 so that pinion 43will engage correctly with intermediate wheel 44.

The lower pivot shank 46 of the magnetic wheel passes through the lowerbridge 36 with a small axial and radial play. During the taking apart ofthe resonator with the cage, the magnetic Wheel 42 remains rigid of thecage borne by the shoulder of the shaft and its upper pivot does notleave its bearing. Means are provided, for example, a stud 53 whichlocates the lower bridge member 36 with respect to base plate 32 beforethe lower pivot enters its bearing.

This arrangement reduces to the strict minimum the size of the lowerbridge 36 of the cage and facilitates the fitting of the resonatorbearing the cage on the base plate 32, without damaging the teeth of thefirst intermediate ard construction elements in particular settings. Itis also possible to pivot the magnetic wheel 42 between the upper bridgeand the lower bridge of the cage. In this case it is not howeverpossible to use stones having standard dimensions, for during theplacing of the resonator with the cage in the re-assembled plate, thereis danger during the vertical movement of the assembly to hit and damagethe teeth of the intermediate wheel 44.

FIGURES 5 and 6 show a modification fulfilling the required conditions.In this construction stones 47 and 48 of the lower hearing are cut by avertical plane in such a way that the edge of these stones pass at acertain distance from the Wheel 44 during the placing of the resonatorwith the cage in the timepiece. The stones 47 and 48 are lodged in thelower bridge 36 and in a plate 49, the vertical surfaces of these stonesbeing aligned with the edge of bridge 36.

In a second modification shown on FIGURE 7, there is used a single smallsize stone 50 aligned with the edge Slof bridge 36 or the stone may beseparated from the edge by a very thin wall.

What is claimed is:

1. In an electronic timepiece including a base plate independentlycarrying both a-movement cage and the foot of a resonator which iselectrically maintained, said resonator constituting the time base andthe driving member for said movement, a bearing cage independent fromsaid movement and connected rigidly to said foot, said hearing cageincluding a ratchet wheel, and a pawl for transmitting motion from saidresonator to said ratchet wheel.

2. A timepiece as claimed in claim 1 comprising a cam rotatable withsaid ratchet wheel, and an oscillatory system driven by said cam anddriving a second ratchet wheel geared to said movement.

3. A timepiece as claimed in claim 1 and comprising a magnetiSed polarwheel driven by said ratchet wheel and driving magnetically a secondpolar wheel which is mechanically free of said first polar wheel andwhich in turn drives said movement.

4. A timepiece as claimed in claim 3 wherein said second polar wheel hasa spindle and the end of the spindle is journalled in said bearing cageand the other end of said spindle is journalled in said base plate.

5. Timepiece according to claim 1, wherein said bearing cage consists ofa lower and an upper bridge, said lower bridge being located above theplate of the movement and the ratchet wheel being pivoted between saidbridges.

6. Timepiece according to claim 5, wherein said lower bridge of saidbearing cage is secured to said upper bridge.

7. Timepiece according to claim 1, wherein said bearing cage comprisestwo bridges secured against the upper and lower surfaces of the footsecuring the resonator to the plate.

References Cited UNITED STATES PATENTS 2,625,004 1/1953 Bush et al.58-23 2,700,272 1/1955 Trichel 5856 FOREIGN PATENTS 769,614 3/1957 GreatBritain.

RICHARD B. WILKINSON, Primary Examiner E. C. SIMMONS, Assistant Examiner

